Package coilmq :: Package store :: Package sa :: Class SAQueue

Class SAQueue

object --+    
         |    
QueueStore --+
             |
            SAQueue

A QueueStore implementation that stores messages in a database and uses SQLAlchemy to interface with the database.

Note that this implementation does not actually use the ORM capabilities of SQLAlchemy, but simply uses SQLAlchemy for the DB abstraction for SQL building and DDL (table creation).

This coilmq.store.sa.model.setup_tables function is used to actually define (& create) the database tables. This class also depends on the init_model method have been called to define the coilmq.store.sa.model.Session class-like callable (and the engine & metadata).

Finally, this class does not explicitly use shared data (db connections); a new Session is created in each method. The actual implementation is handled using SQLAlchemy scoped sessions, which provide thread-local Session class-like callables. As a result of deferring that to the SA layer, we don't need to use synchronization locks to guard calls to the methods in this store implementation.

Instance Methods

enqueue(self, destination, frame)
Store message (frame) for specified destinationination.

stompclient.frame.Frame

dequeue(self, destination)
Removes and returns an item from the queue (or None if no items in queue).

bool

has_frames(self, destination)
Whether specified queue has any frames.

int

size(self, destination)
Size of the queue for specified destination.

set

destinations(self)
Provides a list of destinations (queue "addresses") available.

close(self)
Closes the databases, freeing any resources (and flushing any unsaved changes to disk).

Inherited from QueueStore: __init__, frames, requeue

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __sizeof__, __str__, __subclasshook__

Class Variables
Inherited from `QueueStore`: `__metaclass__`

Instance Variables
Inherited from `QueueStore`: `log`

Properties
Inherited from `object`: `__class__`

Method Details

enqueue(self, destination, frame)

Store message (frame) for specified destinationination.

Parameters:

destination (str) - The destinationination queue name for this message (frame).
frame (stompclient.frame.Frame) - The message (frame) to send to specified destinationination.

Overrides: QueueStore.enqueue